disposal wells

The headlines were clear: fracking causes earthquakes. Yesterday an important study came out in Science that found a strong link between the injection of wastewater into deep underground wells and nearby earthquakes. Hydraulic fracturing—used in the process of developing shale gas and oil wells—also involves pumping millions of gallons of water and chemicals underground, in an effort to essentially pry fossil fuels out of tight layers of rock. Therefore, fracking causes quakes. Right? Not exactly. The Science study, led by researchers from Columbia University’s Earth Institute, looked at deep wastewater disposal wells, which are different than the shale gas wells where fracking actually takes place in the way that a landfill is different from a garbage can. Injection wells are designed to hold the wastewater created by drilling many wells—for that reason, far more water goes into a deep injection well than into a fracked gas or oil well. The researchers found that the pressure created by pumping millions upon millions of gallons underground seemed to put extra pressure on nearby fault lines—so much so that when major quakes struck thousands of miles away, like the March 2011 quake in northern Japan that caused an epic tsunami, the resulting seismic waves could trigger swarms of small quakes near the injection sites. It’s the injection wells—not the fracking per se—that are specifically linked to those temblors in this study. Does that mean fracking is off the hook? Not really. Many of the fluid-injection wells studied by the Science researchers—in Texas, Oklahoma, Colorado, Arkansas and Ohio—have been in operation much longer than shale gas and oil fracking has been active. But each shale gas well can produce several million gallons of wastewater, and in much of the country, that wastewater is disposed by being pumped into one of the more than 30,000 deep disposal wells around the country. As the oil and gas industry likes to point out, underground disposal wells are an accepted way to dispose of wastewater, and they’ve been used for decades. But as the shale gas and oil boom ramps up, the industry will be